Midwest braces for more possible tornadoes

Many Americans are bracing themselves for the possibility of more flooding and tornadoes. Weather Channel meteorologist Kelly Cass reports.

By Andrew Rafferty and Ian Johnston, NBC News

Americans in the Midwest begin another week bracing for severe weather, with forecasters warning of possible tornadoes for a large swath of the country -- including the suburbs of Oklahoma City that were pummeled last week.

The first three days of the week bring the possibility of tornadoes, forecasters said, but the biggest threat is on Wednesday.

The National Weather Service on Monday issued tornado warnings and severe thunderstorm watches for parts of Kansas and Nebraska that remain in effect until 1 a.m. ET. Several tornadoes were reported to the National Weather Service throughout the day in Nebraska, Colorado and Wyoming, but none are believed to have caused any damage.

On Tuesday, storms packing heavy rainfall will bring the possibility of large hail, dangerous wind gusts and tornadoes to thecentral U.S., according to Weather Channel meteorologist Greg Forbes.

Heavy rain pummeled south Texas on Sunday, while in Vermont emergency crews restored power to homes after a late-season snow storm, NBC's Michelle Franzen reports.

Forbes said that the most severe threat of tornadoes will occur Wednesday, with a huge portion of the country from Texas up to North Dakota at risk. That includes Moore, Okla., where an EF5 tornado blew through last Monday and killed 24 people.

“A tornado outbreak is possible over the central part of the U.S. in the traditional Tornado Ally area,” said Forbes.

The predictions for potentially devastating storms follow a Memorial Day weekend full of wild weather. Three people died in powerful floods in the San Antonio, Texas, area over the weekend. Some 130 people had to be rescued during a storm that dumped morethan a foot of rain on the city in just 24 hours. Cars and a city bus were swept off the streets.

And though the start of June is less than a week away, parts of upstate New York and Vermont were buried under as much as 34 inches of snow, according to weather.com. The heavy snow brought down trees and power lines.

Temperatures in the snow-laced areas are expected to return to levels more typical of late May in coming days.

Though many throughout the country were disappointed that the weekend known as the unofficial start to summer was colder than usual, those in the Northeast will not have to wait long for things to heat up.

According to the National Weather Service, "A big warm front is forecast to lift northeast through the Ohio Valley by Wednesday afternoon." Those from Boston to Washington, D.C., will experience summer-like temperatures that may reach up to 90 degrees comeFriday.